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Wirral man

skywatcher evostar ed80 pro do i need a flattener?

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Hi all just been looking through the net and noticed people are using field flatteners but do i need one? plus i have seen the Skywatcher .85x Reducer/Flattener for ED80 does it have to be this one or can you use any again all new to me 

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Hi.

I use my ED80 with a Canon 70D and with either an Atik 414osc or 428mono. I've used it with and without the flattener and I can see no difference at all with the Atiks - and it gives me a slight improvement in the size of the target for galaxies. I think there is a marginal benefit with the Canon 70D. For larger targets (nebula) I use it whatever the camera.

Not a waste of money but not an absolute necessity as far as I am concerned. Maybe so with a much bigger sensor.

HTH

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1 hour ago, Adreneline said:

Hi.

I use my ED80 with a Canon 70D and with either an Atik 414osc or 428mono. I've used it with and without the flattener and I can see no difference at all with the Atiks - and it gives me a slight improvement in the size of the target for galaxies. I think there is a marginal benefit with the Canon 70D. For larger targets (nebula) I use it whatever the camera.

Not a waste of money but not an absolute necessity as far as I am concerned. Maybe so with a much bigger sensor.

HTH

this is what i thought i came from using a d5100 aps-c sensor and i know have and use asi1600mm a 4/3 sensor and given these flatteners cost around a £170 its money that can be spent else where

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Quote

Skywatcher .85x Reducer/Flattener for ED80

I would say this is a better bet than a flattener, it screws directly to the drawtube and eliminates tilt on the camera.

Carole 

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Posted (edited)

I found a signifcant benefit with the flattener you've mentioned.

M31 without it, and NGC7000 with it, using a Canon DSLR APS-C sensor.

 

 

 

 

M31.jpg

NGC7000_MONO.jpg

A2E155BA-E0D6-4898-9EC3-382B2570E44D.jpeg

Edited by tooth_dr
Added third RGB image with .85x FF

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I would say with a ASI1600 you will definitely benefit from a flattener.  @tooth_dr's example above is excellent and shows the elongation you will almost certainly see in the corners with this sensor without one.

There isn't only one to use, but it does need to work with the focal ratio of your scope (f/7.5) and many will only work between f/5 and f/6 so research before buying a third party one.  The SW one is "matched" in this regard and, as rightly pointed out by @carastro will screw fit which helps with a more rigid connection. 

An investment for sure, but for AP one well worthwhile.

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7 hours ago, tooth_dr said:

I found a signifcant benefit with the flattener you've mentioned.

M31 without it, and NGC7000 with it, using a Canon DSLR APS-C sensor.

 

 

 

 

M31.jpg

NGC7000_MONO.jpg

Is that rgb verses HA?

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Just now, newbie alert said:

Is that rgb verses HA?

 

Yes it is. The only images I could find on my Work PC earlier! Does it matter?

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It doesn't matter to me but as a comparison a ha image is going to give you smaller stars..more contrast in the dust..a true comparison would be of the same target. image scale will be slightly different..stars will be different at the edges..ive always used a reducer since I wasn't impressed too much without it..with a reducer it's in a different league..  nice images by the way Adam

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Posted (edited)
20 minutes ago, newbie alert said:

but as a comparison a ha image is going to give you smaller stars..more contrast in the dust..a true comparison would be of the same target. image scale will be slightly different..stars will be different at the edges..

What I posted I hope will have been useful to the OP regarding the potential purchase of a FF 👍🏼👍🏼

Edited by tooth_dr

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30 minutes ago, newbie alert said:

It doesn't matter to me but as a comparison a ha image is going to give you smaller stars..more contrast in the dust..a true comparison would be of the same target. image scale will be slightly different..stars will be different at the edges..ive always used a reducer since I wasn't impressed too much without it..with a reducer it's in a different league..  nice images by the way Adam

It doesn't really have anything to do with the size of the stars, it's about the elongation of them and the pattern of it showing the need for a flattener.  Elongation would show in Ha as well as RGB.

The 4/3 sensor on the ASI1600 is a reasonable size and the image will need to be cropped without a FF if you want round stars across the image.

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52 minutes ago, RayD said:

The 4/3 sensor on the ASI1600 is a reasonable size and the image will need to be cropped without a FF if you want round stars across the image.

You are talking about the stars at the edges without the FF being elongated even with the HA data? Yes I agree as the field won't be flat...but as a separate  subject  ha data does have smaller stars than rgb,would I be correct in saying this?

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Posted (edited)
18 minutes ago, newbie alert said:

You are talking about the stars at the edges without the FF being elongated even with the HA data? Yes I agree as the field won't be flat...but as a separate  subject  ha data does have smaller stars than rgb,would I be correct in saying this?

Oh definitely, you are absolutely spot on, the stars would typically appear smaller/tighter in a Ha only image.  This would be the same with or without the FF, but without it you would have noticeable elongation at the edges with this combination.  The ED80 is quite a small objective and the ASI sensor is a reasonable size.

There's definitely no need for a FF in all combinations.  You can often get away without one on a setup with a big image circle OTA and a small sensor camera, but as the sensor size increases, if you don't want to crop, then the need for the FF increases.

Edited by RayD
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right folks looks like im spending yet more money then plus for my narrowband it will give me a slightly wider fov and speed up the scope.. yet again many thanks!!

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22 hours ago, Wirral man said:

right folks looks like im spending yet more money then plus for my narrowband it will give me a slightly wider fov and speed up the scope.. yet again many thanks!!

It is a rather expensive hobby, isnt it?! 

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What bits does one need to connect a Canon DSLR directly to a SW ED80 without using the SW x0.85 flattener/reducer? 

I have all the connectors necessary to connect my canon 450D using the flattener, but not without. Sometimes when imaging a smaller target I think it might be useful to connect directly. 

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